Apparatus for regrinding and polishing perforated diamonds.



L. POPPE. APPARATUS FOR REGRINDING AND POLISHING PLHULA 'LBD DIAMONDS.

APPLICATION FILED MAY 14, 19h,

Patented Feb. 14, 1911.

Leap p01:

L. POPPE.

APPARATUS FOR REGRINDING AND POLISHING PERFORATED DIAMONDS.

APPLICATION FILED MAY 1%, 1910,

Patented Feb. 14, 1911.

2 SHEETS-SHEET 2.

Urn mien: Leopold Poppa /3. yWI/qi L/ UNITED sT TEs PATENT OFFICE.

LEOPOLD POPPE, or BERLIN, GERMANY.

APPARATUS ron REGRI'NDING AND POLISHING PERFORATED DIAMONDS.) if:

To all whom it may concern:

Be it known that I, Lsorou) Form, a subject of the King of Saxony, and residing at Berlin, Germany, have invented certain new and useful Improvements in Apparatus for Regrinding and Polishing Perforated'Diamonds, of which the following is a specifiing and locating with its point in the hole in the stone which rotates'round a vertical axis; and the objects of my improvement are, first, to afford facilities for obtaining the desired form of the wall -of.the stone; sec- 0nd, to avoid and remove cracks and sharp edges on the stones; third, to reduce the power which has the tendency to bend the needle and' to loose or tobreak'ofi the rotating stone. 1 I

In order that my invention may be clearly understood reference will be made to the ac- 'eompanying drawing, wherein Figures 1 and 2 are front and end elevations, respectively, ofone form of my apparatus; Fig. 3 is a top plan view of the ro or rail which loosely holds and moves the shafts of the tools; Figs. 4 and 5 are plan views, partly shown in horizontal section on the line A-B in Fig. 2. showing various parts of the apparatusrFig. (S is an -elevation of a spindle which is adjustable in height in the machine frame and serves simultaneously as a grooved or step pulley for the rotating work-table; Fig. 7 is a longitudinal section through a pi ece.of work or carrier having a diamond secured therein; Figs. 8 and 9 are elevations, on an enlarged scale, showing the tool resting vertically and slantingly, respectively, without positive guidance in the diamond; Figs. 10, 11 and 12 illustrate he operation of thetool in the diamond and the final shape of the here or hole on a scale about twenty times the natural size.

Referring firstly to Fig. 1, two rails or bars 0, d are held by means of columns b on a machine bed a at a suitable distance apart and from the table, the bottom rail 0 being mounted in suclrmanner that it can be loweged, after the nuts holding it have been loened for example.

Specification of Letters Patent. Application filed May 14, 1910. Serial No. 561,386

Patented Feb. 14, 1911.

As shown in Figs. 1 and 6, in the bottom rail 0 an optional number of bearings m, e g. 10, are so arranged that they can be adjusted in height and fixed by means of screws m. In each adjustable bearingm rests the point of a spindle is which is provided with grooves 70 if necessary of vari-' ous sizes, as a grooved or step pulley, is journaled above in th'erail (l and. earries thereabove a detanhable tablei Two arms 0 on the one rail, e. g. the rail d, rve for guiding a .rail or bar f which is, provi ded with holes, 8 (Fig. 3) and ean movereadily horizontally to and freon tlles.ill"ms iji The tool is a needle n (FlgeJi; j'pncl 9) which is provided with aspeeiallyffshaped point and preferably held in afhol low,

slotted holderg by means of clam ingiflring or slide o, as shown in Figs. 8 "an 9, "The top ends of the holders 9 are inserted into each spindle rests a ,plateb in whose center the piece of work/ or diamond is secured. Above the rail a driving ring g is adjustablyj secured on each holder. I The rail 7 can be driven and the spindles, step pulleys or grooved pulleys-k provided with the tables i can be rotated inj o'p'tional manner. One for'm'of driving clevi'ceis rep resented by way of example in Figs.1, 2 4 and 5. Behind the spindleskis journaled a shaft 22 provided with a loose and a fast driving pulley t and an the shaftt is keyed for each of thespindles l: a grooved pulley t (Fig. 4). from which the one end of the cord is led directly to the spindle 7c and the other is conducted out of the plane of the groove by means ofan idler 'v. as

the holes 8 in the rail 7. On the table of I shown in Figs. 3' and 4Q At one end of the carrying a weight f. In this illustrative 0 embodiment all the spindles k and their tables 21 are rotated rapidly simultaneously and the rail f is reciprocated horizontally and imparts an oscillatory motion to the holders 7 carrying the tools n. The stroke of the rail f corresponds a proximately to the angle m'shown by dotte ines in Fig. 9.

This 0 referred, the stroke of rail f can he ma e variable by making the crank ,wf

' (Figs. 1 and 2) adjustable radially.

As mentioned above, the perforated diamond j issecured a plate h (Fig, '7), namel byfmeansof alead plug :1. The

-plate has 'a conical orfunnel-shaped cavity leading to the diamond j andis mounted centrally to the axis of rotation on the table 1 5b means ofwax, as shown in F igs, 7, 8 an 9,*and the point of each necdlcn 1s mserted; into the hole 'of a diamond, a wellknown polishingmedium, in general a mix-] ture of diamond dust'and oil, being previous'ly applied to the point of the needle.

While the diamondis rapidlyv rotating the 1 top part of the needle oscillates and its slant- :ing position corresponds to the desired conicity of the hole in the diamond. But as fthe'driving ring 9 of the shaft 9 rests on the rail f at a certain, previously-determinable slanting position ig. 2)), thus before -the.stroke of the rail corresponding to the distance m is finished toward-the left-hand .25:

.or right-hand side, when the needle is in its "extreme slanting position it is raised in the hole-inthe diamond and, when rocking back into the" perpendicular posit-ion, is released again for falling unim 'icdedly, sothat it eohstantlyrsts on the wall of the hole,

\ j grinds the-hole'round in the vertical position and' always r qvides for distributing the polishmg me 1um..'

-As has been frequently emphasized hereinbefore and will be readily understood, 'the' tool, 1'. efathe needle 72, is not guidedpositively until it is being-withdrawn from the hole, so that even when tlmdia'mond is not secured exactly centric'ally the desired action 'f-for the mount h of the stone to be forced'ofl nevertheless takes place and it is impossible the table i.

When it is required-that the needle 71, shall oscillate only toward one side, say the angle a; as indicated in Figs. 8 and 11, the needle is raised from a certain moment onward and lies loosely on the walls of the hole so that the three zones 7' 7' i (F ig; 12) of the hole are worked correspondingly to the pur pose in viewl Owing to the needle lying loosely against, and to its being drawn over, the walls of the hole not only is the desired, slightly curved form of thewall obtained, but also cracks and sharp edges'are avoided Tand removed. Such an action was imposcariseihe working part wasguided posi- -tively in the same,'so that-the tool could only exceptionally and for a, short time lie against the walls of the hole, particularly in the. ver

ti'cal position of the needle, IlIl'WhlCl] irregular holes beginning from the smallest diam'ete'r are principally ground round., r

I claim 1 In apparatus for regrinding and polishing 5 holes in diamonds, the combination,- with a revoluble table carrying a drilled diamond, of alperforated horizontal rail mounted to reciprocate horizontally above the table, a holder freely" movable in a hole in said rail and carryin a needle resting in the hole in the diamon a driving ring secured adjust-- ably on said-holder above said. rail and means for rotating said table and simul ta-neously reciprocating said rail, the osi: tion of said ring on said holder relative y to .saitl-rail beingisuch that, when the holder isvertical, the ring is raised above the rail but,

when the holder is being oscillated into its extreme slanting position, the ring rests on and is driven positively by the rail before.

sible with the devices known heretofore be- 

